cattle egrets

[(Richard Johnson)]

Hi David

There has been very little work done on egrets in northern
Australia so it
is uncertain what movement there might be from there into
southern
Australia.  Obviously some Cattle Egrets must have come south
in order to
have colonised NSW in the first place.  Just how regular this
is and what
number of birds might be involved is beyond us at this stage.

I read your email on the source of Cattle egrets in Vic with some interest. It's generally assumed that Australia was colonised by the Cattle Egret from the north southwards, but I reckon it's possible that the reverse may have applied in northern Qld. In no way do I claim to be an expert on these birds but base my thoughts on evidence collected in the field over a longish period.
As I understand it, Cattle Egrets have been in southern Qld for a long time now.  I believe the first record of Cattle Egret at Townsville came in the mid-1960's. They remained a very scarce vagrant for a long time. In the mid-80's a group of us were banding ibis and egrets in a rookery on Ross river, T'ville and found that there were a few nesting Cattle Egrets ( about 3 nests from memory). At that time, Cattle Egrets were still virtually unknown - I certainly never saw them despite many, many hours in the local wetlands. Since then numbers around T'ville have increased to the point that they are relatively common. I left the city after 20 years residence in 1990 so am not in touch as much as I would like, but I see the birds on every visit I have made since. Having watched flocks flying up the river at dusk, I suspect that there may be a colony on Ross River Dam somewhere. Over the last 3-4 years I have also encountered birds flying over the Bruce Highway south of Sarina. It appears that a colony exists in that area somewhere. [As an aside, the last time I drove through that area I had the pleasure of seeing a young Peregrine Falcon astride its freshly-killed prey - a Cattle Egret - on the highway! As I approached I saw several cars swerve to avoid the unconcerned falcon, so I pulled up and relocated the egret to a bare patch off the road. The falcon circled around, calling - very reluctant to part with the prize - and with a bit of luck it got to eat breakfast without being skittled].
If I'm right about Cattle Egrets being originally scarce in NQ while they were common in northern NSW and southern Qld, but having since undergone a boom in numbers, it could be that southern birds have dispersed northward into NQ (NB your banding controls) and eventually colonised in suitable habitat. Is there any firm evidence to confirm or refute this idea?

Richard
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Richard Johnson
Roma District
Tel: (07) 4622 4266  Fax: (07) 46 22 4151
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